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Massive colliding-wind binaries that host a Wolf–Rayet (WR) star present a potentially important source of dust and chemical enrichment in the interstellar medium. However, the chemical composition and survival of dust formed from such systems is not well understood. The carbon-rich Wolf–Rayet binary WR 140 presents an ideal astrophysical laboratory for investigating these questions, given its well-defined orbital period and predictable dust-formation episodes every 7.93 years around periastron passage. We present observations from our Early Release Science programme (ERS 1349) with the James Webb Space Telescope Mid-Infrared Instrument (MIRI) Medium-Resolution Spectrometer and Imager that reveal the spectral and spatial signatures of nested circumstellar dust shells around WR 140. MIRI medium-resolution spectroscopy of the second dust shell and Imager detections of over 17 shells formed throughout approximately the past 130 years confirm the survival of carbonaceous dust grains from WR 140 that are probably carriers of ‘unidentified infrared’-band features at 6.4 and 7.7 μm. The observations indicate that dust-forming carbon-rich Wolf–Rayet binaries can enrich the interstellar medium with organic compounds and carbonaceous dust.

Cosmic-ray acceleration has been a long-standing mystery 1 , 2 and, despite more than a century of study, we still do not have a complete census of acceleration mechanisms. The collision of strong stellar winds in massive binary systems creates powerful shocks that have been expected to produce high-energy cosmic rays through Fermi acceleration at the shock interface. The accelerated particles should collide with stellar photons or ambient material, producing non-thermal emission observable in X-rays and γ-rays 3 , 4 . The supermassive binary star Eta Carinae (η Car) drives the strongest colliding wind shock in the solar neighbourhood 5 , 6 . Observations with non-focusing high-energy observatories indicate a high-energy source near η Car, but have been unable to conclusively identify η Car as the source because of their relatively poor angular resolution 7 – 9 . Here we present direct focussing observations of the non-thermal source in the extremely hard X-ray band, which is found to be spatially coincident with the star within several arc-seconds. These observations show that the source of non-thermal X-rays varies with the orbital phase of the binary, and that the photon index of the emission is similar to that derived through analysis of the γ-ray spectrum. This is conclusive evidence that the high-energy emission indeed originates from non-thermal particles accelerated at colliding wind shocks. Massive binary star Eta Carinae drives the strongest colliding wind shock in the solar neighbourhood. Using NuSTAR and XMM-Newton data, Eta Car has now been convincingly shown to accelerate non-thermal particles, contributing to the Galactic cosmic ray flux.

Dust and glowing hydrogen obscure the Carina complex at visible wavelengths. An X-ray study, combined with infrared surveys, provides knowledge of newly formed stellar associations and past supernova explosions in this system.

The extreme, high‐velocity interstellar absorption‐line profiles toward η Carinae and 16 neighboring stars in Trumpler 16 are examined, including several new sight lines observed in the ultraviolet with theHubble Space Telescopeor in the optical from the Magellan and European Southern Observatories. No two sight lines are identical, but many velocity components are in common. When the velocity scale is shifted to a standard of rest defined by the Carina Nebula emission lines, the symmetries between negative and positive velocities are striking; at least 15 distinct “shells” can be recognized. This circumstance suggests that the complex expanding structures are predominantly in front of the ionizing cluster. There may be a relationship to indications of a supernova remnant in this direction, including a recentChandra X‐Ray Observatoryimage. Interpretations in terms of high‐energy phenomena generated by ongoing star formation possibly on the near side of the giant Hiiregion are also discussed.

Eta Car, with its historical outbursts, visible ejecta and massive, variable winds, continues to challenge both observers and modelers. In just the past five years over 100 papers have been published on this fascinating object. We now know it to be a massive binary system with a 5.54-year period. In January 2009, η Car underwent one of its periodic low-states, associated with periastron passage of the two massive stars. This event was monitored by an intensive multi-wavelength campaign ranging from γ-rays to radio. A large amount of data was collected to test a number of evolving models including 3-D models of the massive interacting winds. August 2009 was an excellent time for observers and theorists to come together and review the accumulated studies, as have occurred in four meetings since 1998 devoted to Eta Car. Indeed, η Car behaved both predictably and unpredictably during this most recent periastron, spurring timely discussions.

High-dispersion spectroscopic observations of the neutral Homunculus and the ionized Little Homunculus, ejecta of η Car, are being analyzed to determine the relative abundances of metals. Thousands of lines of neutral and singly-ionized metals and molecules seen in the Homunculus suggest that this oxygen-, carbon-poor, nitrogen-, helium-rich gas contains very different dust grains likely devoid of metal oxides. The gas to dust ratio is likely much larger than the canonical 100:1 implying that the 12 M⊙ estimate of the ejecta is a lower limit.